Production of dimensionally stable hardened copolymer monohydric phenol, dihydric phenol-aldehyde resinous mass



Patented Mar. 18, 1952 PRODUCTION OF DIMENSIONALLY STABLE HARDENED 'COPOLYMER MONOHYDRIC PHENOL, DIHYDRIC PHENOL-ALDEHYDE RESINOUS MASS Philip H. Rhodes, Kingston, Y., assignor, by mesne assignments, to Koppers Company, Inc., a corporation o'f Delaware No Drawing. Application August 15, 1946, Serial No. 690,824

The present invention relates to the manufacture and utilization of reactive phenolic resin syrups.

In one} form of the invention a transparent set-up phenolic type resinous mass containing up to 35% of water is prepared by forming awaterc'ontainingsyrup having present a permanently fusible two-stage phenolic-aldehyde condensation product-,the-phenolic body of which contains at'least 20% of a dihydric or dihydroxy phenol taken on a molar basis, a formaldehydeliberating setting agent in an amount to set and harden the syrup, and a catalyst selected; from the group consisting of acid and alkaline'catalysts. The so-formed syrup is then set at a temperaturevarying between about 60 F. and210 F., and in one form of the invention, between 60 F. and 1 20 1?. within a time period of twelve (12) to forty-eight 8) hours, the water-content of the syrup being retained during the setting and hardening step- If desired the syrup may have added thereto a filler selected from the group consisting of organic and inorganic fillers. The filler may be an inert fibrous fabric or a plurality of fibrous sheets, which rnay be superimposed one on the other.

The invention is directed to the method of preparing the set-up resinous mass and the prodnot; or; articles formed therefrom, said articles being dimensionally stable and free from warpage. J

Theprimary object of the present invention is to produce a set-up phenolic type resinous mass in a relatively, simple, efiicient, and economical manner, the set-up mass being characterized by dimensional'stability and resistance to solvents. saidset-up mass containing awater-content up to 35%.

It is an additional object of the presentinvention to prepare set-up resinous masses from; an aqueous syrup-said set-up resinous masses c'ontaining atleast a major portion of the aqueous content-of the syrup, this being efiected bythe procedure herein set forth and by curing at temperatures below the boiling point of water and preferably between 60 F. and 120 F.

. A futher object of the present invention is to prepare set-up resinous masses of the type hereinz'set-forth which, although containing a high Water content, are transparent.

thefollowing'examplesi" The present invention' will b illustrated by 15 Claims. (01. 260-54) Example I A syrup is prepared by first producing a copolymer phenol resorcinol-formaldehyde, permanently fusible resin and thereafter converting the same into a syrup, the phenolic body of said resin being 50% phenol and 50% resorcinol.

The copolymer phenol-resorcinol-aldehyde resin is prepared as follows:

A mixture is made of thefollowing ingredients:

. Grams Phenol (12 mols) 1128 37% formaldehyde solution 660 Oxalic acid crystals 5 Water 50 The phenol is melted and poured into a suitable reaction vessel which may be a steel kettle provided with a steam jacket, a horse shoe agitator, a reflux condenser, a thermometer well, and an addition or sampling hole.. To the phenol there is added, first, 660 grams of formaldehyde solution. The oxalic acid is then dissolved in 50 grams of Water and while the contents of the kettle are being stirred by the agitator, the re sulting oxalic acid solution is added. Steam is then admitted to the jacket and the contents of the kettle are gradually warmed to reflux state. The kettle is maintained at a gentle reflux, usually at a temperature of 95 to 98 C., until the reaction has proceeded to the point where the formaldehyde is substantially all tied up with the I phenol.

temperature should not exceed 40 to or C;

. However, care must be taken to cool the formaldehyde solution of the resorcin immediately after the resorcin has dissolved in order to prevent any reaction occurring between the resorcin and the formaldehyde. The resorcin solution is advantageously cooled to between 0 and 30 C., but most satisfactorily between 0 and 10 C., and 10 and 20 C., and the solution is maintained in the cooled state until it is added to the reactionproduct present in the kettle. The resorcin solu-" tion may be cooled to a lower temperature than 0 C butthis is usually not necessary or desir 1 able.

The cooled solution of resorcin and formaldehyde is added to the kettle through the reflux just rapidly enough to maintain steady reflux of the contents of the kettle, the reflux temperature usually varying from 94 to 102 C.

After all of the resorcin-formaldehyde solution has been combined with the monohydric phenolaldehyde condensation product, the mixture is maintained under reflux conditions to insure that substantially all of the formaldehyde or other aldehyde present is substantially tied, up. In other words, there should be, in the most desirable form of the method, no free formaldehyde at this stage of the condensation reaction. Usually to minutes are suificient to obtain substantial elimination of all free formaldehyde.

Thereafter, the water present in the composite copolymer product is removed in any suitable,

manner, but preferably by vacuum distillation. The dehydration is effected preferably under a, vacuum of 26 to 28 inches of mercury and a steam pressure of about 50 to 60 pounds. During the course of the dehydration step, between 1100 and 1200 grams of liquidare removed, and of this amount a small proportion, for example, 2.5 to 3.5%, is crude unreacted phenol. When the dehydration has been completed, the kettle is opened andthe liquidresinous mass ispoured oil and allowed to solidify to a brittleresin containing less than .5% to- 1.0% of water, and usually not over .75% as determined by the A. S. T. M. method. The brittle resin is transparent, pale amber in color, and is soluble in spirit solvents.

In the above example, the reaction is carried out between .68- of a mol of formaldehyde and 1 mol of phenol. The molecular ratio of the formaldehyde to the resorcin is also of the same order. In general, the molecular ratio of the formaldehyde to the monohydric, phenolic body mayvary from .5 to .9 of the former to 1.0,of theflatter. The ratiov between the formaldehyde and the resorcin may vary in a like manner. While themolecularratios are of the same order, as'above, pointed out, it is. within the province of the, presentinvention to vary the molecular ratics, of. the component resinous materials and thereby. provide a method ofproducing mixed resins of. a predeterminedmelting point and having a. predetermined curing range;

While, the. reaction in, the kettle between the. monohydric phenol and v formaldehydeis carried outin; the presence of oxalic acid-as the catalyst, it is within the province of the present invention to, use. other catalystsin lieu of the oxalic acid. For examplaanyof. the weak organic acids may be used, such as: citric, tartaric, acetic, and the like. Any of the usual acid. catalysts may be used.. suchas, hydrochloric acid, sulphuric acid, phosphoric acid,. and the like. Whenusing an inorganic acid asa catalyst, it is preferable to use may be desirable to add additional catalysts tothekettle just prior to the addition of the polyhydroxy benzene aldehyde, solution, as for example, a solution of resorcinin formaldehyde.

general; the amount of catalyst used; in carrying out the complete reaction will vary from about .1 to 2 taken upon the combined weight of the monohydric phenol and the dihydroxy benzene used in carrying out the invention. The per-' centage of catalyst is set forth by way of illustration, and as the preferred percentage. Obviously, the amount of catalyst used. will va y depending upon the character of the reacting constituents and the specific manner in which the reaction is carried out.

Instead of, using formaldehyde, other prior art aldehydes may be, used, such as acetaldehyde. paraldehyde, propylaldehyde, the butyl aldehydes, furfuraldchyde, and the like. Instead of using a, single aldehyde, a mixture of aldehydes may be used.

The resin produced from the example above set forth is composed of 50% phenol and 50% resorcin, taken on a molar basis.

Instead of dehydrating the resin to 5% to 1 of water, that is, to an anhydrous state, varying amounts of water may be left in the resin, as for example, up to 10% to 25% taken on the weight of, they resin. The so prepared resin has added thereto a reaction-accelerating agent or acid catalyst whichwill increase the reactivity of a laminating syrup or. the laminating base. prepared therefrom, thuscausing the resin.con.=- tained in the laminating. or casting syrup to cold set at a temperature varying betweenv 60 F. and 120 F. within 48hours and preferablywithin 12 hours.

The. casting. syrup or laminating syrup may be prepared from the following mixture:

2000 grams of the permanently fusible resin prepared as abovesetforth 300.grams of water- 300 grams. of glycerine 30 gramsof oxalic acid crystals The permanently fusible resin may be dis.-

solved' in the solvent medium, and, if necessarythe reaction mass may be heated to effecta sub.-

stantially complete solution of the resin. This is usually best effected by refluxing the mixture at a refluxingtemperature,that is, at or adjacent C., fora suitableperiod'of'time which. for the mixture set forth will approximate 45 minutes, and there will thereby be produced a smooth clear-homogeneoussolution. In the above example the amounts of 'water and glycerine are, respectively, 15%. by. weight taken on theresin. However, the amount: of water and glycerine may greatly vary and still come with The copolymer phenolresorcinolresin is what. maybe-termed a'hydrophilic resin in that .it' will retain a reasonably large proportion of water'- in its cured' condition; that is, a cured'resinofthe type herein described-may contain as'high as 35% of retainedwater and still maintain its transparency. It may be. pointed out that it is possible to cast. two-stage.- resorcinol-aldehyde resins in the presence of. a setting agent: where the resin is utilized as a; water solution: and that.

this is in contradistinction; to the; casting-50f phenolic resins in that it is; impossible to. cast aosazse a phenolic resin which contains water in any .appreciableamount. Further, it maybe stated that it is not known that two-stage straight phenolic resins such as straight monohydric phenolic resins have ever been cast.

Referring to one-stage monohydric phenolaldehyde resins as typified by the Bakelite resins, it may be stated that these resins are hydrophobic in character. Consequently during the final settingof these resins, water is thrown out, and because it is incompatible with the cured resin structure, it serves to weaken the latter.

It has been discovered that resorcinol-formaldehyde two-stage permanently fusible resins can be cast in the presence of the Water since the resorcinol-aldehyde permanently fusible resin is hydrophilic in character. As a consequence, the chemical water liberated by the curing reaction, as well as the water originally present in the casting syrup does not lower the strength of the resulting cured casting.

In the above example, the glycerine performs its prior art function of an inhibitor of shrinkage and also acts as a plasticizing agent for the casting or laminated structure. Further, the presence of glycerine or its equivalent increases the hydrophilic characteristics of the resin. Instead of using glycerine other materials may be used. I

The glycerine and its equivalents are characterized by the property of compatibility with the resin component of the syrup in its uncured state and the resulting resin product in its cured state. Instead of using glycerine there maybe used ethylene glycol, cyclohexanol, diethylene glycol, the partial esters and ethers of ethylene glycol and diethylene glycol typified by glycol monoethyl ether, diethylene glycol, monoethyl ether and ethylene glycol monoacetate, said partial ester and ether groups being less than the total number of hydroxyl groups in the polyhydric alcohol. In general, it may be stated that there is present in the casting syrup a material which acts as an inhibitor of shrinkage of the resin in its uncured and cured state and toughens theresin in its cured state.

A further property which should be possessed by the inhibitor of shrinkage is that it should not bleed from the resin after the latter has been cured to its permanently infusible state and should not be capable of being extracted by solvent media acting on the cured resin.

Instead 'of using water as a solvent for the copolymer phenol formaldehyde resin, there may be used in lieu of all orpart of the water other solvents such as commercial solventalcohol,

acetone, ethyl acetate, or other alcohols, ketones,

esters, or other. organic solvents known to dissolve phenolic aldehyde resins.

In order to make the casting or laminating syrup cold-setting, it is to be noted that there has been added to the casting syrup thirty parts .of oxalic acid crystals which act as an acid catalyst to make the two-stage permanently fusible casting or laminating syrup cold-settingin the presence of a setting agent, that is, a syrup in the. presence of a setting agent will set at temperatures varying between 60 Rand 120 F. within .48 hours and -preferably within twelve hours. Instead of using oxalic acid there may be. employed the strong mineral acids such as sulphuric, hydrochloric, sulfonic, or the strong organic acids, such as trichloroacetic, tartaric, benzene; sulfonic, and the salts of these acids with "weak bases, as for example, aluminum chloride,

6 zinc chloride, ammonium sulfate, and the like. The amount of acid catalyst required to convert the two-stage copolymer permanently fusible phenol resorcinol aldehyde resin, as for example, a phenol resorcinol formaldehyde resin in the presence of a formaldehyde liberating setting agent will in general vary from about /2 of 1% to 10% taken on the weight of the resin solids, and preferably of 1% to 5%.

The laminating or casting resin can be made cold-setting by adding thereto an acid catalyst asset forth, or, alternatively, the laminating or casting syrup may be made cold-setting by employing an alkaline catalyst, as for example, sodium hydroxide. The amount of alkaline catalyst required will vary from about 1% to about 10% taken on the weight of the resin solids in the laminating or casting solutions and, preferably, about 1% to 5%.

It is preferred to use an acid catalyst to produce the laminating or casting syrup of the pres.- ent invention sincethe acid catalyzed syrup pro.- duces set up masses of lighter color and greater dimensional stability than the alkaline catalyzed syrup. By greater dimensional stability is meant that the shrinkage is less when the casting syrup is acid catalyzed.

It is desired to point out that the casting resins of the present invention have a much lower shrinkage coefficient than the straight phenolic resins such as the Bakelite resins which are cast in the cold and cured in the hot state, that is, at temperatures above 160 F. It is customary in the prior art to cure the one-stage phenolic aldehyde resins, as for example, one-stage phenol formaldehyde resins, the so-called Bakelite resins at 160 F. or above. The higher the temperature, the greater the shrinkage.

In accordance with the present invention the dihydric phenol aldehyde resins, as for example, the resorcinol-aldehyde resins or the copolymer monohydric phenol dihydric phenol-aldehyde res ins are cured in the cold, thatis, at temperatures varying from about 60 F. to F. and sometimes from temperatures varying from about 60 F. and about 90 F. The cold casting of these two-stage permanently fusible resins in the presence of water or other solvents produces appreciably less shrinkage than occurs when the prior art straight phenolics such as Bakelite are cast at temperaturesabove F. In short, the shrinkage of the ordinary monohydric phenol aldehyde resins such as Bakelite is around 1%, whereas, the shrinkage of resins produced by utilizing the casting syrups of the present invention vary betweenabout 05% and about .5%.

The casting or laminating syrups of the present invention may have the toughness of the cured resinous materials reatly increased byiadd-r ing thereto a toughening agent in amounts varying from about 1% to 30% and preferably 1% to 10% taken on the weight of the resin solids'present in the casting syrup, said additional-toughening agents being selected from the group consisting of vinyl polymers, such as polyvinylalcohol, polyvinyl acetate, and the like, the polymeric olefin polysulphides, such as ethylene polysulphides, cellulose derivatives, such as methyl cellulose, carboxyethyl cellulose, and the like, said toughening agents and their equivalents being compatible with the casting or laminating syrup and the setting agents employed to set the lamie nating'syrup. 1 g;

When using the syrups of the present invention. as laminating agents, it is preferred that .theviscosity thereof vary between band 20 poises.

iThe casting syrups ofthe present invention preferably have aviscositybetween 10 and 30 poises The casting syrups herein set'forth which are two-stage permanently fusible resorcinol-aldehyde, as for example, resorcinol formaldehyde containing syrups or copolymer monohydric dihydric phenol aldehyde resin-containing syrups,

maybe set by adding thereto asuitable amount of a formaldehyde-liberatingsetting agent, as for example, a solution of formaldehyde in ethylene glycol, commercial.37% aqueous formaldehyde-a solution of formaldehyde in commercial solvent alcohol, a solution of formaldehyde in commerciaLisopropyl alcohol, a solution of dimethylol urea, thermosetting liquid urea resins, a solution of polymethylol melamines, phenolic casting syrups, and trioxane.

' In general, the amount of setting-agent necessary to set the resin is an amount necessary to increase .the molar ratio of formaldehyde to phenolic bodyfrom less than 1:1 in a permanently fusible resin to 1:1 or greater. In general,-. the amount ofsetting agent may vary from 5%.or1-10% to .as high as.100% or 150% taken on'ithe weightof the resin subject to the limitation that there must be at least enough to raise thev ratio. of the total aldehyde of the cast- .ingzorilaminating syrup to the total phenolic body presentinthe resin to at least 1:1. It is not known that excesses in setting agent greater thanz25% or. 30% affect the quality of the finished. product. containing an acid catalyst and a formaldehydeliberating setting agent together with fillers and-[or tougheners if desired may be cast'by pourings the casting syrup into a mould, said mould being composed of metallic substances, glass, or glazed ceramics or metals; waxed wooden moulds, or anymould materialwhich is a'solid at room temperature, that is between 60 F. and 120 F. andfwhich is non-adherent to the casting syrup.

Thecasting is allowed to remain inthe mould for a period of from to 48 hours-and preferably to 24 hours at a temperature varying between 60 F. and120 F.

More specifically, the casting syrup of the present-example was pouredinto an open porcelain crucible and allowed to stand at 75 F. for aperiod of three hours; at the end of whichtim'e it had reached a degree of cure such that it could'not be penetrated 'by .a sharp metal stylus forced manually across its surface witha-pressure of approximately lbs. The shrinkage from the sidesof the dish was approximately 0.002 inch per inch. The-sample was transparent andilight red in color and was sufficiently tough so that when it was bounced on a concrete-floor it didnotbreak.

"The syrup of Example I having'present therein .a setting-agent comprising a 37% solution ;of

formaldehyde in ethylene glycol was used toprepare laminates from a standard grade of bleached unsized laminating paper. The individual laminae were dipped into the laminating syrup and allowed to drain for about minutes'untilthe excess syrup was removed from each-of the laminae. They were then assembled in superimposed relationship until -10 layers had-been' built up. The stack of layers was then subjected to a pressure of 2 lbs. per square'inch. The-assembly wasallowed to stand for a period of 8-hoursatthe end of which time the pressure was-removed, the'resin having cured sufficiently to-give a' relatively high degree of stability to the structure.

The so-prepared casting syrup At the endof an additional 40'hours shear'test specimens were out from the panels. The average-shear-strength of 5 shear specimens was-415 pounds'per squareinch.

.Erample II -A- straight two-stage permanently fusible resorcinol formaldehyde resin was prepared as follows:

-About 2500-grams of resorcinol are reactedwith 500 .grams of 37%v formaldehyde solution in a suitahlereaction 'vessel. Preferably, the reaction vessel comprises a steam jacketed kettle equipped with ahorse-shoeagitator, a reflux condenser, and :an addition valve. The formaldehyde .is added to the resorcin present in the vessel and thereafterthe jacket is gradually heated sothat the temperature of the 'resorcinol formaldehyde mixture is slowly raised to C; as the resorcin goes into solution, great care being taken that the mixture does notbecome too ebullient, and boil over. As the temperature reaches 100 C., the steam jacket is taken: out of circuit and then about .750 grams of 37% formaldehyde are gradually added to the kettle. The rate of addition is governed by the temperature of the mixture. The particular mixture above set'forth is not permitted to become heated to over C., no boiling over occurring. As'the formaldehyde is added to the partially reacted mass, heat is generated and the rate of reaction is controlled so that the heatgiven off is not sufficient to cause the mass to boilover. Usually the formaldehyde is added gradually in increments, the time of addition being'usually about 1 -to 1 hours. However, this will vary with the :size of the reaction mass and on large scale production, may take as long as two or three hours.

-As soon as the formaldehyde is all added to the kettle the-reflux temperature is maintained by the addition of heatas necessary 'fora period of 10 to- 20 minutes to insure complete, reaction of theadded formaldehyde. The kettle operation ischanged from one of reflux to one of distillation, and 'theresin'in the kettle'is dehydrated by distillation until .the temperature reaches C. to- C. "The latter phases of the dehydration may be done under vacuum if .desired. At the completion of the dehydration the resin ,in the kettle may be removed and cooled to form a brittle two-stage permanently fusible resorcinol formaldehyde resin.

This resin was compounded to forma castin syrup base in accordance with. the following:

Grams Permanently fusible resorcinol-formaldehyde resin 2000 Water 400 Ethylene glycol. 400 Oxalic acid crystals a "a".-- 15 In making the syrup base the permanently fusible resjorcinol formaldehyde resin produced as'above wasdissolvedin 400gms. of water, and therewas added thereto, 400 gms. of ethylene glycol and 15 grams of oxalic acid to thereby produce .a casting or laminating syrup .base which in the. presence ofa setting agent is converted into the finallaminating or casting syrup. To the syrup base preparedas abovesetforth there is added 780 grams of 37% commercial aqueous formaldehyde. Laminating paper similar tothatset forth in Example I was dipped into the laminating syrup containing permag 2,589, 9 nently fusible resin and formaldehyde and an acid catalyst, and the laminae were allowed to drain for approximately 15 minutes after which they were assembled in panel form. The assembled laminae were cured under a. pressure of 2 lbs. per square inch at a temperature of 90 F. for approximately 7 hours at the end of which time the pressure was removed and the panel was allowed to age to obtain maximum cure for an additional 36 hours at'the end of 10 which time shear test specimens were cut out of the panel and tested for shear strength. The average shear values of 5 specimens was ,450 lbs. persquare inch. J r

The shear test set forth was made by cutting strips from the panel 1 inch wide, milling grooves lfinch apart on opposite sides of said strips. said grooves having a depth of /3 of the thickness of the specimen. The specimens were then mounted in,1a Rie'hle shot-loading testing machine and pulled apart with tensile loading until shear failure had occurred. The shear value was calculated as the load in pounds required to shean'the one square inch area under test.

A portion of the Example II syrup containing 2 5 the setting agent was poured into an open porcelain' crucible and allowed to stand for about two hours at 80 F. at the end of whichtime it had been cured to such a state. thatit could not be penetrated by a metal stylus pressed manually against its surface with a force of approximately 10 lbs. The article cast in the manner described was allowed to stand for. an additional. 36 hours, at the end of which time it was not adversely affected byimmersion in alcohol, ace tone, concentrated sulphuric acid or. it normal sodium hydroxide. The shrinkage from the sides'of the porcelain mould was approximately 0.002 inch, per square inch. The cast, article. which was transparent had a light cherry red 40 color, and when bounced on a concrete floor did not break. a

Example III Preparation and utilization of a casting or laminating syrup produced from an alkaline catalyzed permanently fusible copolymer resin: in which the phenolic body is 10% phenol and 90%" resorcinol based on the total molar quantity of phenols in the phenolic body of the resin.

.-.The following ingredients are mixed in the followingproportions:

'The phenol is melted in a reactionkettle and then'formaldehyde is introduced therein followed. by; the addition of the sodium hydroxide which 69 has been previously dissolved in water. Under agitation the mixture is gradually heated to reflux and maintained there until the formaldee hyde is subs'tantially completely reacted with the! phenol to forrn'a primary undehydrated phenolv aldehyde condensation product. 3 1 j Separately 2970 grams of resorcin are dissolved in 1485 grams of 37% formaldehyde solution in a'seco'nd reaction kettle. Heat is applied gradually'to prevent any sudden exothermic reactionfl 7 After-solution occurs, heating is continued until; an exothermic reaction ,is initiated, which us e ally occurs at a temperature between 65 C. to Obviously. ,thetemperature at which'the" exothermic-reaction will occur'wilr'depe'ndto 75 character of the reactin some extent on the constituents and other physical conditions thereof. At the conclusion of the exothermic reaction, the resulting hot liquid resin solution is added gradually to the phenol-formaldehyde undehydrated primary condensation product. During the addition, the contents of the reaction kettle are maintained at reflux. The lat ter varies usually from about C. to 102 C. After the resorcin-formaldehyde primary condensation product has been added to the phenol aldehyde condensation product present in the first reaction kettle, the contents thereof are maintained under reflux conditions for a period of time sufficient to assure the inter-condensation of the primary phenol-formaldehyde condensation product with the primary resorcinol formaldehyde condensation product. When using the above set forth quantities of reactants, usually about 15 to 30 minutes additional refluxing is desirable. This timelimit is merely illustrative and is not byway of limitation. final refluxing period should be suiiicient, as stated, to effect inter-condensation of the primary condensation products and produce a substantially homogeneous liquid resin. The completion of. the inter-condensation step is usually evidenced by the substantially complete absence of any free formaldehyde.

Thereafter, the inter-condensation product is subjected to distillation for-the purpose of removing the water present in the condensation products and to eiiect further condensation and polymerization of the initial inter-condensation product.

The distillation is continued until temperature reaches approximately C. to

= C. at which point the resin is substantially dehydrated. The resin may thenbe removed.

from the kettle and cooled to form a brittle permanently fusible copolymer phenol resorcinol formaldehyde resin.

A laminating or casting syrup base was pre-' pared from the so-produced resin by mixing therewith the following ingredients in the fol-' lowing proportions:

. In preparing the laminatinggor casting syrup base the resin was dissolved as in Example I, and then the 12 N sodium hydroxide was added.

Thereafter to the syrup base there was added 780' grams of commercial 37% aqueous formaldehyde.

tained. Then the shear specimens were cut and. the average shear value of the five specimensv was found to be 450 lbs. per sq. in. tested as set.

forth in'Example II.

A casting was made from the Thethe resin" syrup containing the setting agent.- The casting procedure was. identicalwith that set forth in Example 11. Thecasting was cured ata. temperature of about 80 v F. for a period of two hours. This specimen had set or cured so that it couldn't be penetrated by ametal stylus pressedagainst the surface'of' the casting with a force of lbs. persq; in., and the cast object could be removed from the mould; In order forthe cast object to becomefully cured asevidenced by its resistance to solvents theicast object was allowed to age after removal from the mould for a period of '36 hours at a temperature of 80 F. If itis desired to obtain a full cure in a shorter period of time, that is, have the: object attain its maximumset within a" shorter period" of time, as for example, 12 hours, the amount of alkaline catalyst employed should" beincreased. In other words the time of initial and final'set maybe varied between 12 and 48 hours by vary ing'the amount of acid or alkaline catalyst. It is desired to pointout' that the quicker the time for run curethe shorter the working life of the casting or laminating syrup.

I'n" Examples I to III the setting agents were solutions of formaldehyde. It is'possible to;use

other formaldehyde-liberating setting agents, as

iorexample, trioxane, which in the presence of an acid material serves to depolymerize trioxane,1thereby liberating formaldehyde which functions as the reactive setting agent; A' casting syrup base was prepared using a" permanently fusible resorcinol-formaldehyde resin prepared as in Example II. The castingsyrup base was compounded as follows:

Eramp Ze IV Grams Resin 200 Water.

Glycerine Trioxane The resin was dissolved with slight-heating in" a mixture of waterand glycerine, and thetrioxane in molten form was added to the warm resin solutionwhich may be maintained at a-temperatune of' about 70 C. The resulting solution formed a casting or laminating syrup base.- Therewas: then added thereto gms. of a 50 %-solution of benzene sulfonic acid in ethylene glycol. The syrup was then poured into a porcelain casting mould and allowed to stand at 100 for 8 hours at the end of which time it had cured to a hard castingwhich could not be penetratedby a metal stylus pressed manually against its surface with a force ofapproximately 10 lbs. To impart solid re sistance to the casting after removal of the casting from the mould itwas aged for a period of 36- hours. The resulting casting,wascharacterized by a dark transparent ruby-red color. and. could: be bounced onthe floor without crackingor breaking.

While .it has been pointed out .thatin carryin the presence of la formaldehyde-liberating.setting.

agent and a catalyst at temperatures up to the boiling point of the water'whileretaining the water content of "the syrup in the finished article, this. being, in contradistinction to the phenolic resinsin theprior art which because of their .hydrophobic nature release their water during/the setting and hardening step or during the curing operation, thereby formingweak discontinuous articles or masses accompanied by a complete lossof transparency.

. ltihas-been discovered/that in order that the ,mass resulting from the hardening andsetting of'the herein described resinous syrup contain up to a maximum of 35% water, that is, that the water in thesyrup be retained during the curing operation', that the permanently fusible two-stage y-phenolic-ald'ehyde condensation product must contain at least 20% of its total phenolic body 20 taken ona molar basis as a dihydri phenol or dihydroxy, benzene, as for example, resorcinol,

While 12"to; 418' hours are needed to set and hardenlthe' resinous syrup atroom temperature,

:thatis, at temperatures varying between. 60F.

and -12D "F., as theitemperatureis increased to 140? F. to'160"F; or 180 F. or to temperatures belowthe boiling. point of water, the time toset and/orharden or cure will decrease as the temperature increases; and at temperatures between 180F.'to 210 F; cures'may be obtained in as little as5 minutes.

out the present invention it is desirable to setand harden the resin syrup at a temperature varying.

between F. and 120 F. and within a time period of. 12' to 48 hours, it is within the province of theinvention in one of'its forms to set and harden theresin syrup at a temperature varying between 60F." and that temperature at which the water content of the resinous syrup is retained'during thesetting and hardening step, the upper limit thereof being about the boiling 'temperature'of water.

One of the fundamental points .of 'theipresent invention is that the water-containing syrup having present a permanently'fusible two stage phenolic-aldehyde condensation product the phenolicbody of which contains at 'least"20% of adihydric phenol taken on a; molar basis" sets 'in' It'has been discovered that when'the" amount of'water present inthecured article substantially exceeds 35% the article. loses its transparency. and develops aten'dency toward shrinkage and cracking upon ageing: In other words, the

amount of'water'present in the syrup; whether it be from the solutionof the resin; the setting agent; the catalyst, or' formed during reaction. sh'ouldnot exceed 35% of the weight .of the mass produced from curingthe syrup, the lower. water limitof thesyrup being usually about 10%.

Instead of using resorcinol as the dihydric phenol, other dihydroxy-phenols may be used having, three substituted benzene ring positions and'which will react with the aldehydes to produce-permanently fusible resins which will become low temperature reactive with the setting agents herein. set forth and at the temperatures herein set forth.

Examples of'otherdihydric phenoliccompounds are orcin (1)CH3C6H3(3,5) (OH)2, 1 chloro 3,5 dihydroxy benzene, 1 amino 3,5 dihydroxy benzene, .1 nitro 3,5 dihydroxy benzene.

Themonohydricphenol used to'produce the resin may. bephenol perse, thecresols, xylenol commercial .cresylic acid, and the like.

As the example of .a trihydroxy phenol which may be usedi'n-carrying out the present invenglass fabric, mineral fabrics, including asbestos. felt sheet'stock; such as glass felt, and

sisal felts or bats- In producing theiset'upfphenolic type-resinous 13' mass of the present invention any of the prior art fillers may be used, including walnut shell, Airicamnut shell flour, powdered slate, barytes. iron oxides, carbon black, plaster of Paris, Portland cement, bentonite, cellite, nylon, and the like.

The above fillers are examples of organic and in-;

organic fillers. These fillers may be present in the mass in an amount varying from to 50% and, in some cases, to 50% taken on the.

weight of the filled resin syrup.

14 1 30 poises; a reaction-accelerating catalyst and a formaldehyde-liberating setting agent in an amount to set and harden the resin component of the syrup, said set-up and hardened resinous mass being compatible with water and retaining between 10 and 35% of water functioning to inhibit shrinkage during the settingup and hardening of the resulting resinous reaction product,

While sodium hydroxide has been set forth as a suitable alkaline catalytic, agent, to make the resin syrup cold-set, other alkaline catalysts such as potassium, hydroxide, barium hydroxide,-

lithium hydroxide, ammonium hydroxide, and organic bases, such as triethanol amine, ethylenediamine, and the like, may be used. Other alkaline catalysts which may be used are the alkaline salts, as for example, sodium, potassium, orf

lithium carbonates, tribasic sodium phosphate, borax, and the like.

As herein pointed out the syrup of the present invention may be cured in less than an hour or several hours or in less than twelve hours at temperatures varying between 60 F. and 120 F.

by the use of the catalyst herein referred to.

In accordance with the present invention a high water-content which may be diluted to some extent with solvents may be incorporated in the.

laminates. In other words, the set-up resinous mass of the present invention is very compatible with water.

The'syrups of the present invention may be on the acid side or the alkaline side depending upon the kind of filler or laminate which is used in one form of the invention. If the fabric is of a cellulosic nature such as cotton cloth, it is desirable to use a slightly alkaline laminating syrup in order to obviate acid damage to the cellulose. On the other hand, a fabric such as nylon somewhat'more effectively bonded by an acidic laminating syrup than by an alkaline one. The syrup of the present invention does not exhibit the highly corrosive acidity characteristics of the phenol-formaldehyde resins.

The term filler medium as used in the claims denotes that the filler is the medium or, stated difierently, it means a filler medium.

This application is a continuation-in-part of application Ser. No. 614,096 filed September 1945, now U. S. Patent No. 2,524,079.

1. A continuous dimensionally stable set-up and hardened copolym-erized monohydric phenol, dihydric phenol-aldehyde resinous mass the resin component thereof being transparent and consisting of the reaction product of a water-containing syrup containing a syrup base having present a permanently fusible two-stage reaction product of a phenolic body consisting of a monohydric phenol and a dihydric phenol, and an aldehyde which is condensable with and heatreactive with said phenolic body to form a resinous condensation product therewith, said phenolic body containing at least 10% of a monohydric phenol and at least 20% of a dihydric phenolin which the hydroxy groups are on the same carbon ring, the percentages being on a molar basis, said syrup having a viscosity varying between 6 and said hardened resinous mass being resistant to cracking on aging.

2. A dimensionally stable cast and hardened resinous mass, the resin component of which is a transparent copolymer monohydric phenol, dihydric phenol-aldehyde condensation product, said resin component consisting of the reaction product of a water-containing syrup containing a syrup base having present a permanently fusibletwo step reaction product of a phenolic body consisting of a monohydric phenol, and'a dihydric phenol and an aldehyde which is condensible with and heat-reactive with said phenolic body to' form a resin condensation product therewith, said phenolic body containing at least 10% of a monohydric phenol and at least 20% of a dihydric phenol in which the hydroxy groups are on the same carbon ring, the percentages being on a molar basis; a reaction accelerating catalyst; and a formaldehyde-liberating setting agent in an amount to set and harden the syrup, the resin component of said set-up and hardened mass being compatible with and retaining between 10% and 35% of water functioning to inhibit shrinkage during the setting-up and hardening of the cast resinous reaction product, the latter being resistant to cracking on aging.

3. A dimensionally stable cast and hardened resinous mass, the resin component of which is a transparent copolymer monohydric phenol, dihydric phenol-aldehyde condensation .Jproduct, said resin component consisting of the, reaction product of awater-containing syrup containing a [syrup base having present a permanently fusible two step reaction product of a phenolic body consisting of a monohydric phenol, and a dihydric phenol and formaldehyde condensible with said phenolic body to form a resin condensation product therewith, said phenolic body containing at least 10% of a monohydric phenol and at least 20% of a dihydric phenol in which the hydroxy groups are on the same carbon ring, the percentages being on a molar basis; a reaction accelerating catalyst; .and a formaldehyde-liberating setting agent in an amount to set and harden the syrup, the resin component of said set-up and hardened mass being compatible with and retainofamonohydric phenol and at 1east 20% taken on a' molar basis of a dihydric phenol in which the hydroxy groups are on the same carbon ring, and an aldehyde'which is condensible with and heat-reactive with said phenolic body to form a resin condensation product therewith; a reaction accelerating catalyst; and a formaldehyde-liber- 15 ating setting agent. in an: amount to setand harden the syrup, the resin-component of'sald set-up. and hardened mass being compatible with and retaining between 10% and 35% of water functioning to inhibit shrinkage during the setting-up and hardening of the cast resinous reaction product, the latter being resistant to cracking on aging.

5. A dimensionally stable cast and hardened resinous mass, the resin component of which is a transparent copolymer monohydric phenol dihydric phenol-aldehyde condensation product, said resin component consisting of the reaction product of a water-containing syrup containing a syrup base having present a permanently fusible two step reaction product of a phenolic body containing at least 50% taken on a molar basis of .a monohydric phenol and at least 20% taken on a molar basis of a dihydric phenol in which the hydroxy groups are on the same carbon ring, and formaldehyde condensible with said phenolic body to form a resin condensation product therewith; a reaction accelerating catalyst; and a formaldehyde-liberating setting agent in an amount to set and harden the syrup, the resin component of said set-up and hardened mass being compatible with and retaining between and 35% of water functioning to inhibit shrinkageduring the setting-up and hardening of the cast resinous reaction product, the latter being resistant to cracking on aging.

6. A dimensionally stable cast and hardened resinous mass, the resin component of which is a transparent copolymer monohydric phenol dihydric phenol-aldehyde condensation product, said resin component consisting of the reaction product of a water-containing syrup containing a'syrup base having present a permanentlyfusibletwo step reaction product of a phenolic body'containing 50% of a monohydric phenol and 50% of a dihydric phenol in which the hydroxy groups are on the same carbon ring, the percentage of both phenols being taken on a molar basis, and an aldehyde which is condensible with and heat-reactive with said phenolic'body' to form a resin condensation product therewith; a reaction accelerating catalyst; and a formaldehyde-liberating setting agent in an amount to set and harden the syrup, the resin component of said set-up and hardened massbeing compatible with and retaining between and 35% of water functioning to inhibit shrinkage during the setting up and hardening of the cast resinous reaction product, the latter being resistent to cracking on agin 7. A dimensionally stable cast and hardened resinous mass, the resin component of which is a transparent copolymer monohydric phenol dihydric phenol-aldehyde condensation product, said resin component consisting of the reaction product of a water-containing syrup containing a syrup base having present a permanently fusible two step reaction product of a phenolic body containing 50% of a monohydric phenol and 50%- of a dihydric phenol in which the hydroxy groups are on the same carbon ring, the percentage of both phenols being takenon a molar basis, and formaldehyde condensible with said phenolic body to form a resin condensation product therewith; a reaction accelerating catalyst; and a formaldehyde-liberat-- ing setting agent in an amount to set and 16 harden the syrup, the resin component of said set-up and hardened mass being com atible with and retaining between 10% and 35% ofv water functioning to inhibit shrinkage during the setting-up and hardening of the cast resinous reaction product, the latter being resistent to cracking on aging.

8. The cast and hardened resinous mass set forth in claim 2 in which the monohydric phenol is phenol per se and the dihydric phenol is resorcinol. I

9. The cast and ..hardened resinous mass set forth in claim 4 in which the monohydric phenol is phenol per se and the dihydric phenol is resorcinol.

10. The cast and hardened resinous mass set forth in claim 6 in which the monohydric phenol is phenol per se and the dihydric phenol is resorcinol.

11. The cast and hardened resinous mass set forth in claim 5 in which the monohydric phe-- nol is phenol per se and the dihydric phenol is resorcinol.

12. The stable and hardened resinous mass set forth in claim 1 in which the original phenol body which reacts with the aldehyde contains at least 50% of a monohydric phenol and at least 20% of a dihydric phenol in which the hydroxy groups are on the same carbon ring, said percentages being taken on a molar basis.

13. The stable and hardened resinous mass set forth in claim 1 in which the monohydric phenol is phenol per se and the dihydric phenol is resorcinol.

14. The stable and hardened resinous mass set forth in claim 1 in which the original phenol body which reacts with the aldehyde contains at least 50% of a monohydric phenol and at least 20% of a dihydric phenol in which the hydroxy groups are on the same carbon ring, said percentages being taken on a molar basis, the monohydric phenol being phenol per se and the dihydric phenol being resorcinol.

15. The stable and hardened resinous mass set forth in claim 1 in which the original phenol body which reacts with the aldehyde contains 50% of a monohydric phenol and 50% of a dihydric phenol in which thehydroxy groups are on the same carbon ring, the percentages of both phenols being taken on a molar basis, the monohydric phenol being phenol per se and the dihydric phenol being resorcinol. PHILIP I-I. RHODES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,849,109 Novotny Mar. 15, 1932 2,385,370 Norton Sept. 25, 1945 2,385,372 Rhodes Sept. 25, 1945 2,385,373 Rhodes Sept. 25, 1945 2,385,374 Rhodes Sept. 25, 1945 2,398,361 Daniels Apr. 16,. 1946 2,398,388 Norton Apr. 16, 1946 2,414,415 Rhodes Jan. 14, 1947 2,478,943 Rhodes Aug. 16. 1949 FOREIGN PATENTS Number Country Date.

559,590 Great Britain Feb. 25, 1944 

1. A CONTINUOUS DIMENSIONALLY STABLE SET-UP AND HARDENED COPOLYMERIZED MONOHYDRIC PHENOL, DIHYDRIC PHENOL-ALDEHYDE RESINOUS MASS THE RESIN COMPONENT THEREOF BEING TRANSPARENT AND CONSISTING OF THE REACTION PRODUCT OF A WATER-CONTAINING SYRUP CONTAINING A SYRUP BASE HAVING PRESENT A PERMANENTLY FUSIBLE TWO-STAGE REACTION PRODUCT OF A PHENOLIC BODY CONSISTING OF A MONOHYDRIC PHENOL AND A DIHYDRIC PHENOL, AND AN ALDEHYDE WHICH IS CONDENSABLE WITH AND HEATREACTIVE WITH SAID PHENOLIC BODY TO FORM A RESINOUS CONDENSATION PRODUCT THEREWITH, SAID PHENOLIC BODY CONTAINING AT LEAST 10% OF A MONOHYDRIC PHENOL AND AT LEAST 20% OF A DIHYDRIC PHENOL IN WHICH THE HYDROXY GROUPS ARE ON THE SAME CARBON RING, THE PERCENTAGES BEING ON A MOLAR BASIS, SAID SYRUP HAVING A VISCOSITY VARYING BETWEEN 6 AND 30 POISES; A REACTION-ACCELERATING CATALYST AND A FORMALDEHYDE-LIBERATING SETTING AGENT IN AN AMOUNT TO SET AND HARDEN THE RESIN COMPONENT OF THE SYRUP, SAID SET-UP AND HARDENED RESINOUS MASS BEING COMPATIBLE WITH WATER AND RETAINING BETWEEN 10 AND 35% OF WATER FUNCTIONING TO INHIBIT SHRINKAGE DURING THE SETTING UP AND HARDENING OF THE RESULTING RESINOUS REACTION PRODUCT SAID HARDENED RESINOUS MASS BEING RESISTANT TO CRACKING ON AGING. 